Thousands evacuate as Nicaragua volcano spews ash

Nicaragua's tallest volcano has spewed an ash plume up to four kilometres into the atmosphere, prompting the evacuation of hundreds of nearby residents.

There were no immediate reports of injuries or damage, authorities said on Saturday.

The 1,745-metre San Cristobal volcano, located about 150 kilometres north of the capital Managua in the country's volcano-dotted northwest, has been active in recent years, and stirred in mid-2008, when it expelled gas and rumbled with a series of small eruptions.

The government expects to evacuate about 3,000 people from around San Cristobal, though numerous families already have done so on their own, said Guillermo Gonzalez, who heads Sinapred, a government emergency and disaster relief agency.

"A response plan exists for volcano eruptions and every community has clearly defined places for people to go to once they are evacuated," he said.

A gas and ash plume stretched between 3.5 and four kilometres into the atmosphere, Mr Gonzalez said.

The Nicaraguan Institute of Territorial Studies, which monitors the country's volcanoes, said in a preliminary report that "more gas emissions and sporadic explosions" could be expected from San Cristobal.

The volcano is one of the most active along Nicaragua's Pacific coast, according to the institute, and often averages nearly 100 daily seismic movements.

Government spokeswoman Rosario Murillo earlier said authorities were still assessing the strength of the volcanic activity.